This invention relates to chillers utilized in air conditioning systems and more particularly to direct fired absorption chillers that are used in combination with microturbine engines.
As one skilled in this technology knows, the direct fired absorption chillers (DFA) are not widely used in this country and, in fact, are not utilized with microturbine engines. While water fired absorption chillers have been known to use the waste heat generated by microturbines, these systems require the use of heat exchangers to interface with the water fired absorption chiller. One of the main reasons that the microturbine engine cannot effectively be utilized with the DFA is because the temperature of the exhaust gases vary depending on the load and ambient characteristics of the microturbine. As is well known, the DFA utilizes the environmentally compatible combination of water and an absorbent and a burner to generate the heat necessary to carry out the absorption process. Direct fired absorption refrigeration is initiated when higher pressure liquid refrigerant solution form a condenser is discharged through an expansion device and into a lower pressure evaporator and collects therein. Expansion and xe2x80x9cflashingxe2x80x9d of the refrigerant solution occurs and the liquid refrigerant is collected in the sump of the evaporator. There is also the transfer of heat into the collected and cooled refrigerant solution from comparatively warm system water that is pumped through a cooling tower causing the collected refrigerant solution to evaporate, resulting in vapor that is transferred to an absorber where it is absorbed into a refrigerant solution, such as lithium bromide. This process creates a low pressure in the absorber that draws a continuous flow of refrigerant from the evaporator to the absorber, but also causes the vapor to condense as it releases the heat of vaporization in the evaporator. This heat and the heat of dilution produced as the refrigerant condensate mixes with the absorbent and is transferred into a cooling tower water and is carried out of the absorber. The assimilation of water refrigerant dilutes the lithium-bromide refrigerant solution and reduces its affinity for refrigerant vapor. In order to sustain the refrigeration cycle the solution is then reconcentrated by continuously pumping the dilute refrigerant solution from the absorber to a generator where heat is applied to distill the water refrigerant from the absorber. As the water refrigerant is removed by distillation, the re-concentrated lithium-bromide solution is returned through the absorber and to the generator to resume the absorption process, while the liberated refrigerant vapor from the generator is transferred to the cooler condenser and returned to its liquid state as the cooling tower absorbs the heat of condensation carried by vapor. The liquid""s return from the generator to the expansion device completes the cycle. Of course, this type of system replaces the more costly and typical fluorinated hydrocarbon compounds required by vapor compression refrigeration. The DFA system is considered to be stable, non-toxic and readily absorbed and easily separated in large volume during the absorption process.
This invention is principally concerned with producing the heat that is necessary to carry out the absorption process and particularly the waste heat that is generated by a microturbine engine. Although not limited thereto to the microturbines that are utilized for generating electricity is particularly efficacious for use with the direct fired absorption chiller.
As one skilled in this art will appreciate, it is abundantly important that the amount of heat and consistency of the heat source is required to operate the direct fired absorption chiller efficiently. This invention contemplates utilizing the heat discharging from the microturbine engine that is designed to power an electric generator and controlling the heat so that it is at the proper temperature to operate the chiller and that the temperature is controlled to be maintained at a consistent level, i.e. it is held at a constant temperature.
The object of this invention is the combination of a direct fired chiller and the microturbine engine.
A feature of this invention is the interconnection of the recuperator to the direct fired absorption chiller and a controlled by-pass valve that regulates the quantity of waste heat flowing to the chiller and the temperature thereof.